| Title |
Pesearch Paper / Mechanical Behavior : Effect of Cu on Formability of Low Carbon TRIP - Aided High Strength Cold - Rolled Steel Sheets |
| Authors |
임동빈(Dong Bin Im),이창길(Chang Gil Lee),김성준(Sung Joon Kim),박익민(Ik Min Park) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
The main emphasis of the present study has been placed on understanding the effect of Cu on the formability of TRIP-aided cold-rolled steel sheets. Two kinds of 0.15C-1.5Si-1.5Mn (ECO-0) and 0.15C-1.5Si-1.5Mn-0.5Cu (ECO-Cu) cold-rolled steel sheets were prepared. These steel sheets were intercritically annealed at 790-800℃, and isothermally treated at 430℃. Tensile tests and limiting dome height (LDH) tests were conducted, and the changes of retained austenite volume fractions as a function of tensile strain were measured using X-ray diffraction. The ECO-Cu steel sheet had higher volume fraction of retained austenite about 15%, and smaller size of ferrite grains and retained austenite particles than the ECO-0 steel sheet. On the other hand, the stability of retained austenite of the two steel sheets were the same. The tensile properties and the formability of the ECO-Cu steel sheet was superior to the ECO-0 steel sheet, due to high strain hardening rate maintained in the high strain region by the strain induced transformation of retained austenite to martensite. Containing Cu as a tramp element in the TRIP-aided controlled steel sheets showed beneficial effects on the mechanical properties and formability. |